Grab



April 25, 1933. E. v P. DYGGVE GRAB Filed March ll, 1931 Patented Apr. 25, 1.933

STATES -PATENT 31E-Jair. vALnEnrAR fPETERsEN nYGGvE, yor coran-HAGEN, DENMARK, fAssreNo-a -i'ro lKoEFoED, frmUBERG, --MARsTRA-ND sa HEnwlEG, AKT1EsEIrsKABET TITAN,

l VCOPENHAGEN, DENMRK f GRAB w.ippiimioameamiraron-i1,`1931,serialN0.serramentim penmarknarehii.' 1930.

Y ,'Myyinvetionrelates'toa-'grab with jaws, fthe axes f'rotat'ion of which are'xed rela rtivelyto each other in afra-ine, and the upperparts of whichfare in their closed position i Vconnected individually withy a crosshead, the u liso-called `closing crosshead, by a link, preferablyi-a pressure bar. v`vThe cross'head'is connecte'tl with the top piece 'for instance by pullley blocks, so that the effectof thehoistin'g 1 V10. cablestolift the crosshead is increased. The hitherto known bucket grabs of this kind are advantageous because of'their small height, great ,gripping -power and very great closing force, but Vthey yhave the disadvantage of re- Y .15quliring particular means for procuring the `-lVIoreover,theuse.of rigid-guiding rails, or

other proposed guides, as for instance toothed arcs, directly on the jaws require aV great vwidth of the frame throughout itsfull height, j or the: grab is inanyother way given a shape that makesrit yless suited for Vworking in hatehways or the like, because projecting parts of thegrab may seize the coaming. Thepresentv invention has V-for its purpose to improve: grabs of the kind referred to by making itpossible to insure by simple means and .without the use of guiding rails that the jaws oftheA grab assume always during the opening and closing ofthe grab symmetrical 'positions relatively'to the vertical axis of th-e Vi0 grab. The invention also has Vfor its object to sofshape the bucket grab that it tapers upwards andhasno'projecting parts which might seize a hatchway or .the like. The invention also relates to a particularconnection between thelower part of the frame and itsstruts so as to increase the closingforce of the grab land facilitate at the Sametime its opening and make its construction cheaper. r'I`he invent ion will'be described with refer- --ence1to the ydrawing-but is not limited to the embodiments shown therein, Jas" it Vcomprises yany construction falling'withinthe scope of the "appended claims. Similar Ireference characters in the 'drawing refer to similar parts. Fig. 1 shows'dia'grammatically an K-.55

'embodiment ofthe invention inelevation and withthe movable parts shown in'y their closed position in full lines and in their open posif-tion `in broken lines. fFig. Q-shows on wa larger scale' thel guiding of'the closing cross- ,i60

'head of theembodiment in Fig. =1. Figs. "3 anda show'other embodiments of 'the guiding of the closing cross-head. Fig. v 5 shows an embodiment inwhich the broken lines indicate, as in Fig. 1, the open position'of'theg grab, and the full lines indicate the closed position thereof,whereby the guiding `of the closing crosshead corresponds chieflyto that shown in YFie' V1, while the frame is -constructed withlinke'd connections. Fig. 6' a am front view of the embodiment shown in Fig.

5 and with-the movable fp art-'s "shown in the closed position of'thel grab, and "'Fig. 7 .an other modification o f theguiding of the closing crosshead. In Fig. 1, l is a'frame -toa5 which theljaws 3 of the grab aregpivoted by ipivotsQ. 4, 4 are closing cables' running 'overpulleys 5 mounted in aclosing fcrosshead 6 and'other pulleys 7 mounted in the top piece 8 of the frame. '19 is an openingzso cable secured to the said top piece. The upperparts ofthe. jaws, when in closed position, areprovided `or formed with 7toothed arcs-10, as shown intFig. 2. 11, 11. areother toothed arcs on links 12 connecting-the jaws-is5 3 with the crosshead 6 by means of pivots 13, 14` passing through the centres of the arcs 10, 11. The arcs 11V mesh with `each other, while the arcs 10 mesh with,- gear 'wheels 15 mounted on the pivots 14 and meshing-wither) `each-other. The rectilinear guiding ofthe closing crossheadf 6 is obtained bythe Iarcs 10gear wheels 15 and the arcs 11 of links'lQ,

'the way in whichfthese elements 4mesh with ,each other preventing. the crosshead from making any lateral and' rotary motions which itwould be able-to make relative-to the pivots 2, 18, 14, if the crosshead were connectedwith the jaws only by links 12. In the embodiment shown in Fig. '3 the cross-head 6 .is pro- "i100 vided with a guideway 16, in which slides a block 17 carrying a pin 18. On said pin are mounted two links 19, each of which is connected with one of the jaws 3 by a pivot 5 2O so placed that its axis does not coincide with the axis of the pivot 13. As in Fig. 1, the links 12 are provided with toothed sectors 11 meshing with each other. In Fig. 4L is shown an embodiment corresponding essentially'to Fig. 3,1the guide 16 being, however replaced by a two-armed lever 22 pivoted on a stationary pivot 21, the links 19 being secured to the ends of said lever 22. By this arrangement, theuse of arcs 11 on the links 12 is not strictly necessary. j A lateral motion or turning of the closing crosshead is pre- 'vented bythe links 19 and 12, which together cause a rectilinear guiding ot the closing crosshead, from which results again a symmetrical motion ofV the jaws during their opening and closing operations. By the grab shown in Fig. 5 the guiding differs from that of Fig. 1 in this that between the toothed arcs and' gear wheels 15 are provided intermediate gear wheels 23 Vmounted on pivots 24 in the links 12, whereby advantage isobtained mainly that the said arcs 1() and gear wheels may be reduced in size. rlhe Vtrame is constructed with link connections, its lower horizontal part 25, on which the pivots 2 ot the jaws are placed, being not directly connected 'with the struts 26 of the frame, which are instead thereof connected with the jaws by pivots 27' plac-ed oppositely to pivots 13 in relation to a vertical plane through pivots 2, while at their top they are rconnected with the top piece 8 by pivots 28 and guided in a well-known manner krela- 'tive to each other by meshing. Thereby, in the l'irst place a'greater gripping force is p obtained, as the pressure in the struts 26 during the closing ofthe grab gives a moment relative to the pivots 2, which lare in this case toy be vconsidered as the stationary axes of rotation of the jaws, thesaid moment acting to close the grab, and secondlyan easier opening of the grab, the weight of the jaws and Y of the horizontal part of the i'rame aii'ordl'ing duringthe opening a great moment relative to the pivots 27, this moment acting to open the grab'. Moreover a longer way is obtained for the force in the closing cables, since to the way of the closing crosshead must be added the way covered by the top piece during the opening .because of the link connections.V The top piece is `prevented in a well-known way from lateral or turning movements for example by providing the top ends of the struts with intermeshing teeth. Finally, the advantage is obtained by the use of links in aframe with stationary` pivot points for the jaws, insteadofthe old constructions having rigid frames of the same kind, in `that the' diiiicult rivetings corre- 65 s'ponding to the great forces in question are avoided and the parts of the frame may simply be carried out as tension and compression members without bending strains. Fig. 6 shows that the grab, as seen from the front, has a smooth shape tapering upwardly, the elements necessary to the guiding of the closing crosshead projecting nowhere outside of the struts of the frame. Moreover it will be seen fromV Figs.'1, 5 and 6 that according to the invention the right 75 and left jaw of the grab may be madey completely alike. The height of the grab is very small in proportionV to the wide opening, whereby amongst other advantages an increased stability is'obtained. The embodi- 80 ment shown in Fig. 7 is distinguished by a particularly simple construction. The closingv crosshead 6 carries a plate 29 provided withlslots 30 in'whichslide pins 31 on the jaws 3, when the grab is opened and closetlf As the pins 31 can be moved only in the paths fixed by the slots, it is understood that a lproper guiding 'of the closing crosshead and jaws can be obtained. Instead of slots 30 being provided in the plateV 29 a Vplate ordm) plates can be used having cam edges cooperating with the pins 31, which cam edges are ot' such a shape, that the desired guiding operation is obtained. In the drawing the links 12 are provided with toothed arcs 11 and95 journalled at 14. However the links l2 can also be pivoted by a common pivot, in which case the toothed arcs 11 will be dispensed with. Insteadk of a pulley connection, or the like, between the closing crosshead and the top piece of the grab the necessary closing force maybe obtained in any other wellknown manner, for example by means of a diiferential pulley or by an electric motorM arranged in the grab in combination with' 105 suitable gearing.

I claim:

1. A grab comprising a frame, jaws having their axes of rotation fixed in said frame rela-n tiveto each other, a closing crosshead, pivot-'110 Vally links connecting said crosshead with the uppermost portions of said jaws, and means for vertically guiding said closing crosshead relative to said frame and said jaws, said means comprising intermeshing toothedarcs on said links, toothed arcs on the jaws, and intermeshing gear wheels mounted onl the pivots connecting said links with said closing crosshead and coacting with said last named arcs.

2. A grab comprising a frame, jaws having their axes of rotation fixed in said frame re1- ative to eachother, a closing crosshead, links connecting said crosshead with the upper-A most portions of said jaws, and other links connecting said jaws indirectly with said closing crosshead.

3. A grab comprising a frame, jaws having their axes of rotation iixed in the frame relative to each other, a closingcrosshead, and

Laos-,45o

means for vertically guiding the crosshead comprising links connecting said crosshead with the uppermost portions of said jaws, pins carried by the jaws, and plates carried by the crosshead and having cam formations cooperating with said pins.

4. A grab comprising a frame, jaws pivoted at relatively fixed points to said frame, a closing crosshead, and connections between the jaws and the crosshead, entirely independent of any connection of either the jaws or the crosshead with the frame, to hold the vertical axis of the crosshead coincident with the vertical axis of symmetry of the jaws during opening and closing movements of the jaws.

5. A grab comprising aframe, jaws pivoted at relatively fixed points to said frame, a closing crosshead, and means comprising connections solely between the jaws and the crosshead to hold the vertical axis of the crosshead coincident with the vertical axis of symmetry of the jaws during opening and closing movements of the jaws.

6. A grab comprising a frame, jaws pivoted at relatively fixed points to said frame, a closing crosshead, and means comprising link and cooperating gear connections solely between the jaws and the crosshead to hold the vertical axis of the crosshead coincident with the vertical axis of symmetry of the jaws during opening and closing movements of the jaws.

7 A grab comprising a frame, jaws pivoted at relatively ixed points to said frame, a closing crosshead, links pivotally connected at adjacent ends to the crosshead and at their outer ends pivotally connected to the jaws, and other connections solely between the jaws and the crosshead cooperating with said links to hold the vertical axis of the crosshead coincident with the vertical axis of symmetry of the jaws during opening and closing movements of the jaws.

8. A grab comprising a frame inclusive of a bottom part and struts separate therefrom,

jaws having spaced pivotal connections with the bottom part and said struts, respectively,

a closing crosshead, and means entirely inde` pendent of any connection of either the jaws or the crosshead with the frame for vertically guiding the crosshead during opening and closing movements of the jaws, said means comprising links pivotally connecting the crosshead with the jaws, and cooperating gear connections between the jaws and the crosshead.

In testimony whereof I a'Iix my signature.

EJGIL VALDEMAR PETERSEN DYGGVE. 

